Electrochromic (EC) and thermochromic (TC) materials are of much interest for “smart” windows which combine energy efficiency with the provision of indoor comfort. This paper summarizes results from several recent studies related to nanoparticles of transparent and electrically conducting ITO (i.e., In2O3:Sn) and of thermochromic VO2. Specifically, we consider (i) the use of ITO nanoparticles in polaronic EC devices in order to suppress near-infrared solar transmittance, (ii) performance limits for plasmonic EC devices embodying ITO nanoparticles, and (iii) ITO-VO2-based nanocomposites with joint low thermal emittance and TC properties, and with Mg-doping of the VO2 as a means for boosting the luminous transmittance. Both experimental and theoretical results are presented.

The present article will describe the science and technology of titanium aluminide (TiAl) alloys and the engineering development of TiAl for commercial aircraft engine applications. The GEnxTM engine is the first commercial aircraft engine that is flying titanium aluminide (alloy 4822) blades and it represents a major advance in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines in its class. The GEnxTM uses the latest materials and design processes to reduce weight, improve performance, and reduce maintenance costs.

GE’s TiAl low-pressure turbine blade production status will be discussed along with the history of implementation. In 2006, GE began to explore near net shape casting as an alternative to the initial overstock conventional gravity casting plus machining approach. To date, more than 40,000 TiAl low-pressure turbine blades have been manufactured for the GEnxTM 1B (Boeing 787) and the GEnxTM 2B (Boeing 747-8) applications. The implementation of TiAl in other GE and non-GE engines will also be discussed.

This paper reports on the development and results to date of a new strategy to disseminate a well-validated, successful science communication workshop program to multiple campuses hosting National Science Foundation (NSF) Research Experience for Undergraduates or REU-like research programs. The REU Science Communication Workshop program (REU SCW) is based on the premise that the most effective pedagogy for science communication skills development is one in which students practice iteratively using their own research material, with expert coaching and facilitated peer feedback. After testing several models for widespread dissemination, the most promising capacity-building strategy is one that scaffolds the traditional “train-the-trainer” approach with a new “piggyback” professional development model.

Zinc Oxide (ZnO) Thin-Film Transistors (TFTs) using Aluminum (Al) and Aluminum-doped zinc Oxide (AZO) as Source-Drain (S-D) contacts are reported. The fabrication process was carried out using five photolithography steps with a maximum processing temperature of 100 °C, which makes the process compatible with flexible/transparent applications. The AZO and ZnO films were deposited using Pulsed Laser Deposition (PLD). Aluminum was deposited using ebeam. The devices showed mobilities >10 cm2/V-s, threshold voltage in the range of 7 V and On/Off current ratios >105. The resistance analysis showed that AZO is a better contact with lower contact resistance as identified in the TFTs. The AZO and ZnO stacks characterized by UV-V shows an optical transmission >80 %.

We demonstrate the three-dimensional arrangement of silica microparticles in body-centered cubic lattice structure using both a relief pattern formed in the film of the azopolymer and silica micro particles dispersed in a nematic liquid crystal. In the method, firstly, the square lattice relief structures with the spacing of 2000 nm and the depth of 400 nm were formed on the azopolymer film by twice exposure to two beam interference patterns with coherent light of 488 nm in wavelength from Ar ion laser. Next, a nematic liquid crystal (5CB) containing 2000 nm diam. silica microparticles, with the surface modified with silane coupling reagent giving rise to homeotropic texture, was dropped on the relief structure on the azopolymer. The two dimensional square lattice structures of the micropaticles were formed spontaneously in an isotropic to nematic phase transition. Finally, the microparticles were three-dimensionally arranged by using optical tweezers. The microparticles were successfully stacked in a four-step pyramid structure with body centered tetragonal lattice structure.

Nanoparticle functionalization and assembly is undergoing a period of challenging yet exciting development. Much of this research effort has been focused on the development of new functionalities that might enable strategically-directed assembly of nanoparticles into structures that can be utilized in other important applications.

In order to determine the success of such experiments, researchers often prepare a dried sample and study the assembly patterns with electron microscopy. However, these imaging techniques can be expensive and do not provide a complete illustration of what the three dimensional nanoparticle assemblies truly look like in solution. Moreover, sample preparation presents its own challenges. Most notably, sample preparation may cause alteration to the individual assemblies or unwanted aggregation of the assemblies upon removal of the solution.

To address these concerns, assemblies of anisotropic nanoparticles were tracked free-floating in solution with differential interference contrast (DIC) microscopy. DIC microscopy is an optical technique based on interferometry with high lateral resolution and shallow depth of field. After functionalizing gold and silver nanoparticles for self-assembly, aliquots of the nanoparticle solutions were examined in real-time. Nanoparticle assemblies were observed undergoing rotations, internal vibrations, structural modifications, and interactions with other assemblies. Observations of the dynamic behaviors of nanoparticle assemblies serve as a complement to imaging with electron microscopy and provide new insights into the actual assembly process.

Polystyrene (PS), polymethyl-methacrylate (PMMA) and multi-walled carbon nanotubes (MWNT) were used to fabricate conductive nanocomposites using various mixing methods, followed by compression molding to analyze their electrical properties. The main objective of this research project was to evaluate how using different mixing techniques alter the composite microstructure and hence the properties of the resultant composite material. Three fabrication techniques were selected to be investigated: mechanical mixing, melt-mixing, and solution mixing. The concentration of the fillers was kept constant at 2 wt% MWNT to simplify comparisons. After mixing, the composite mixtures were compression molded at the same temperature of 180°C. It was found that each mixing method yielded uniquely different AC conductivity profiles which can be attributed to how the fabrication method used affected the arrangement of the CNTs in the composite structure. This newfound control of the electrical properties of the composite materials could definitely be useful to researchers because one can choose the proper fabrication technique based on what properties are desired.

We have investigated the atomistic structure of radiation-induced defects in CeO2 formed under 200 keV electron irradiation. Dislocation loops on {111} habit planes are observed, and they grow accompanying strong strain-field. Atomic resolution scanning transmission electron microscopy (STEM) observations with high angle annular dark-field (HAADF) and annular bright-field (ABF) imaging techniques showed that no additional Ce layers are inserted at the position of the dislocation loop, and that strong distortion and expansion is induced around the dislocation loops. These results are discussed that dislocation loops formed under electron irradiation are non-stoichiometric defects consist of oxygen interstitials.

The dynamic features of Al2O3 - polytetrafluoroethylene (PTFE) and Al - PTFE reactions in non-isothermal conditions are presented. The Differential Scanning Calorimetry (DSC) and High-Speed Temperature Scanner (HSTS) were used to characterize the Al2O3/Al – PTFE reactions at different heating rates. The study shows that the HSTS instrument can give more information about the reaction mechanism and kinetics than the conventional DSC measurements. In this work we show that high heating rates may reveal exothermic reaction between Al2O3 and PTFE that were previously unidentified. The PTFE can potentially remove the oxide layer from aluminum in the initial period of the reaction and increase the direct contact area between oxygen and aluminum, which increases the reaction velocity and improves the energy release abilities of the system.

We like to report a novel conductive film containing graphene-silver nanohybrids from the process of solution coating and annealing at low-temperature for melting silver nanoparticles (AgNPs) into interconnected Ag matrice on surface. The fabrication required the assistance of a home-made polymeric dispersant, poly(oxyethylene)-segmented imide (POE-imide), for homogenize the AgNPs and graphene in hybridized form. The intermediate dispersion of AgNPs at 10–25 nm diameter on the surface of 2D-graphene were characterized and subsequently subjected to solution coating into thin films. Under the annealing temperature as low as 160 °C, the films exhibited a high electric conductivity or low sheet resistance at 2.4×10–1 Ω/sq (equivalent to 7.9×104 S/cm). It is noteworthy that the significant point of low-temperature annealing at 160–170 °C that is attributed to the fast deterioration and degradation of the POE-imide organics kinetically before the AgNP coalescence and melting. Furthermore, the comparisons of using silicate clays and carbon nanotubes in replacing the 2D graphene for hybridizing Ag had revealed the different morphologies in Ag networks. The findings of using the polymeric dispersion for synthesizing nanohybrids may open up a new avenue for making films with integrated properties of flexibility, transparency and high conductivity for a host of electronic applications.

Physical vapor deposition, in combination with gas-aggregation (PVD-GA), is a controllable method for creation of diverse nanoparticle structures. Given the size effects that dominate the physics of nanoparticles, a particular advantage of the PVD-GA technique is the compatibility with in situ mass filtering of the nanocluster beam.

In the current work, PVD-GA has been utilized to deposit Ag and Si nanoparticles. Nanoparticles were analyzed using in situ quadrupole mass spectrometry (charge/mass ratio), atomic force microscopy (nanoparticle height), and transmission electron microscopy (nanocluster diameter & crystallinity). The results for particle size distribution were cross-correlated, with excellent agreement.

Different growth methods & conditions were explored, resulting in controlled differences in the measured particle size distributions and surface coverage. A novel growth configuration utilizing a conventional sputter source in combination with a linear magnetron allowed a significant (fivefold) increase in Ag cluster yield.

Poly(3-hexylthiophene)/Titania (P3HT/TiO2) heterojunction has been widely studied in the field of hybrid solar cells. Usually, organic dyes shift the neat TiO2 absorption edge toward the visible range improving the conversion efficiency or/and the TiO2 surface is modified with ligands in order to increase the electron transport. On the other hand, copper sulfide, non-toxic semiconductor, has been included in bulk organic P3HT based solar cell, increasing the photocurrent density of devices. Therefore, we propose the use of copper sulfide in the hybrid TiO2/P3HT heterojunction to determine its effect in the performance of TiO2/P3HT solar cell. Copper sulfide nanocrystals (CuxS) were synthesized at 230 °C, 240 °C and 260 °C and, they were mixed with P3HT in order to form P3HT:CuxS bulk heterojunctions. Scattered grains and irregular morphology in the final topography of the reference device (P3HT/TiO2 heterojunction) were observed by AFM, while a granular morphology and a few pores like craters were observed in the devices containing P3HT:CuxS bulk heterojunctions. Chalcocite phase (Cu2S) was obtained at 230 and 240°C and, digenite (Cu1.8S) phase at 260°C, both copper sulfide phases are very promising for solar cells. Despite this, poor rectifications in the devices were found in the current-voltage curves of the devices containing copper sulfide nanocrystals in contrast to the P3HT/TiO2 cell (device without nanocrystals), it could be due to the current leakage or recombination process in the copper sulfide/TiO2 interface. It suggests future work in order to improve the devices.

Erbium excited state deactivation is studied for two fluorinated complexes based on N-(P,P-ditetrafluorophosphinoyl-P,P-ditetrafluorophenyl phosphinimidates and N-(P,P-dipentafluoro phosphinoyl)-P,P-dipentafluorophenyl phosphinimidates ligands. We show that the substitution of a fluorine atom in para-position by an hydrogen atom on each phenyl ring of the perfluorinated organic ligand results in a decrease in near infrared luminescence lifetimes from 800 µs to 70 µs when measured under vacuum on sublimated powder samples. These experiments show that the introduction of C-H bonds, although outside the first coordination sphere of the erbium ion, can still induce a one order of magnitude decrease in its excited state lifetime. The found lifetime however is still longer than most reported partially fluorinated complexes, which opens the way for new functionalized complexes.

CdSe quantum dots of hexagonal Wurtzite crystal structure with an average diameter of ∼7 nm were synthesized and processed for bulk heterojunction solar cell applications. The UV-Vis absorption spectrum shows an excitonic peak at 625 nm and at 635 nm in synthesized and dual ligand exchanged samples, respectively. The synthesized quantum dots were successively ligand exchanged by pyridine and 2-propanethiol to remove the TOPO ligands on quantum dot surface and then hybrid solar cell devices were fabricated. Initially the weight ratio was optimized by using pyridine capped CdSe blend with P3HT polymer as an active layer in chloroform as a solvent on the patterned ITO glass. Then dual ligand exchanged CdSe was compared with pyridine optimized samples. The maximum solar cell conversion efficiency of 1.21% was achieved with Jsc of 4.1 mA/cm-2, VOC of 0.51 and FF of 44 compared to the optimized pyridine capped CdSe quantum dots where efficiency of 0.74% with Jsc of 2.15 mA/cm-2, VOC of 0.53 was observed. The increase in solar cell efficiency was attributed to the better ligand exchanged and additional treatment with 2-propanethiol at ambient temperature. Such an exchange of organic ligands by successive ligand exchanger will open new domain for hybrid solar cell research. The morphology of QDs and microstructures of the heterojunction active layer (P3HT:CdSe) were examined by using TEM, XRD, UV-Vis spectra, and IV curve techniques.

A complete dry processing route is developed for the fabrication of thermally-conductive carbon nanotube (CNT)-copper oxide (CuOx) heterostructures. This was achieved by the deposition of copper (Cu) onto CNTs and subsequent annealing in Ar and air environment to convert the coated Cu into CuOx nanoparticles. The survivability and diameters of CNTs were studied to ensure their integrity after the multiple processing steps and annealing temperatures (400 °C). The as-produced CNTs, air/Ar-annealed CNTs, Cu-coated CNTs, and CNT-CuOx heterostructures were characterized to study their structure, phase, and morphology using microscopy, elemental analysis, X-ray diffraction, and sheet resistance. It was observed that CNTs could survive the processing conditions and became coated with CuOx nanoparticles. The sheet resistance of CNTs coated with CuOx nanoparticles was ∼4 times greater than the as-produced CNTs. The Raman spectroscopy-based estimation of thermal conductivity of CNTs and CNT-CuOx heterostructures showed 2-7 times enhancement for the latter as compared to pure CuOx. In conclusion, such hybrid CNT-based heterostructures are promising for applications in thermal management.

To date, many studies have been carried out to investigate the use of semiconductive diamonds in industrial applications. In these studies, it has been necessary to deposit high-quality crystalline diamond thin films on large-area substrates. Hot-filament chemical vapor deposition (HFCVD) has been a useful method for generating these thin films. While large-area silicon (Si) substrates are easily obtainable and inexpensive and Si is a suitable material for the deposition of diamond thin films, because of the large mismatch of the lattice constants of Si and diamond, it is usually difficult to grow epitaxial diamond films on Si substrates. Therefore, insertion of a buffer layer comprised of a material with a lattice constant between those of Si and diamond is required. Silicon carbide (SiC), which is readily obtained by carbonization of the Si surface, is a candidate material for such a buffer layer. Therefore, in this study, a char layer was formed on a Si surface using HFCVD equipment and analyzed from various perspectives.

In this paper, a microporous-containing graphene oxide/polystyrene (M-GO/PS) was designed and prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of PS from GO surface and then crossrlinking by carbon tetrachloride. The structures of the molecular brush of PS and the related crosslinking M-GO/PS were determined by FTIR, TG, SEM and nitrogen adsorption-desorption analysis. The experimental results showed that PS molecular brush were successfully grown on to the surface of GO. After crosslinking, the PS component was crosslinked into many round nanoparticles with a diameter of 20-30 nm, and therefore the specific surface area of GO/PS obviously increased. This kind of porous M-GO/PS composite was promising for the application in adsorption-desorption energy storage areas.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired infections (HAI). HAI affect approximately 1.7 million patients each year in the U.S., resulting in up to 100,000 excess deaths, which leads to an estimated cost of more than $35 billion per year. Hence, there is an urgent clinical need to develop new therapies to reduce infections, without resorting to the use of antibiotics for which bacteria are developing a resistance towards. In this study, we designed superparamagnetic iron-oxide nanoparticles (SPION) to treat antibiotic-resistant biofilms and showed that SPION efficacy increases when they are used in combination with fructose.

Electrocatalytic activity and stability of platinum nanocubes and nanospheres were comparatively investigated towards methanol oxidation reaction. The results indicate that the {100}-bounded Pt nanocubes exhibit not only higher catalytic activity but also higher stability compared with the mixed crystallographic facet-terminated Pt nanospheres.

Density functional theory calculations are used to study the equilibrium energetics of protons on the surface and in the bulk of Y-doped BaZrO3. It is shown that protonic species in direct contact with Y dopants have energies lower than in perfect BaZrO3 by up to 0.4 eV. This energetic stabilization is achieved when the protonic species is in direct contact with two Y dopants. On the (001) surface of BaZrO3, protonic species are found to be energetically more stable than in the bulk by 1.1 eV and 1.6 eV on the BaO and ZrO2 surface terminations, respectively. At these terminations, the energy of protons recover the bulk value after penetrating three surface layers, and the energy cost associated with bulk incorporation is larger than 1 eV.